1. Field of the Invention
This invention relates to a separator for alkaline batteries, particularly zinc-silver oxide batteries using silver oxide or peroxide as cathode and zinc as anode, and nickel-zinc secondary batteries or other batteries using zinc as negative active material, as well as to a method of producing such separator. The separator is not only high in resistance to oxidation and alkalies but also it has the high ability to block the trans-migration of ions dissolved from a negative or positive active material.
2. Description of the Prior Art
The conventional zinc-silver oxide battery uses a separator made of regenerated cellulose membrane that retards the transport of dissolved silver hydroxide [Ag(OH).sub.2.sup.-] from the positive electrode to the negative electrode. The membrane is itself oxidized with the silver hydroxide ions which in turn are reduced and form the deposit of metallic silver on the separator, thereby retarding the transport of silver hydroxide ions to the negative electrode. However, the oxidized membrane decays as a result of deterioration. In addition, the membrane is inherently susceptible to the oxygen evolved at the cathode and is not adequately alkali-resistant. For this reason, the conventional separator does not withstand extended use and the cell using it has only a limited cycle life.